We had a problem recently crop up with the toilet in the master bath. All of a sudden, the water has slowly started draining out of the bowl after it refills. The water refills to its normal level, but then slowly (over the course of an hour or so) drops down until there's barely any water left in the bowl. The toilet seems to run just fine, but the low water level makes me nervous. Does anyone know what could be the cause of this and how it can be fixed?
Thanks in advance for your help!